Device for vaporising and diffusing oils

ABSTRACT

A device which uses a heat source for heating and diffusing fragrant oils or insecticidal oils. The oil is contained in a reservoir remote from the heat source and the device comprises means for transferring the oil from a reservoir to a surface of a heat-absorbing means wherein heat from the heat source is transferred by conduction to said surface to volatilise the oil.

This is a Continuation-in-Part of U.S. Ser. No. 10/483,546 filed Jul.14, 2004 now U.S. Pat. No. 7,014,819.

This invention is concerned with devices that diffuse and vaporise oils,e.g. fragrant oils or insecticide oils, using heat source, e.g. aradiant heat source or a by conduction or convection.

Candles may be used as a heat source to diffuse fragrances. Typically afragrant oil is incorporated in the body of a candle and the fragrantoil is released as the candle burns. However, the fragrant oils that maybe used may be limited because they must not only be capable of beingmixed in the candle matrix, they must also be capable of burning toensure that the candle operates correctly.

Alternative devices are known that overcome the problems associated withfragrance-containing candles. The devices diffuse fragrant oils locatedin a reservoir external of a candle. Thus in U.S. Pat. No. 4,781,895 afragrant oil contained in a porous cartridge, is contained in areservoir supported directly above a candle which is burnt. The bottomof the reservoir is heated by the flame and thereby acts as a hot platewhich heats the cartridge and volatilises the fragrant oil. However,application of a direct flame to an oil-containing cartridge may lead tooverheating and combustion of the oil. Furthermore, as the cartridgecontains a finite amount of oil which is not replenishable, the highinitial concentration of oil will vaporise quickly to produce a burst offragrance, but the release of oil will reduce quickly consistent withdecreasing oil concentration in the cartridge. Still further, as thecandle recedes so its heating effect on the reservoir will diminish andfurther exacerbate the uncontrolled vaporisation rate of the oil.

Another device is described in U.S. Pat. No. 5,911,955. This deviceagain uses candle heat to volatilise a fragrant oil contained in areservoir external of a candle. However, in this device the candle heatis not applied directly to the fragrant oil; rather the heat from theflame is conducted to the reservoir along radiation-absorbing fingerswhich extend outwardly from the candle flame and communicate with thereservoir. The reservoir is open to the atmosphere to permit egress ofthe vaporised oil. However, an open reservoir permits access to the oilby users and could also permit spillage of the oil, for example onto theflame. Further, as the heat from the candle must be transferred over arelatively large distance by conduction across the radiation-absorbingfingers, there will be a delay between lighting the candle and effectivevaporisation. Still further, as the candle recedes, the heating effectof the flame on the fingers will diminish resulting once more in anuneven vaporisation rate of the oil.

It has now been found that it is possible to make a device thatvolatilises fragrant oils or insecticide oils and that is substantiallyfree of disadvantages associated with the prior art devices.

The invention therefore provides in one of its aspects a device forvaporising and diffusing oils comprising a heat source and a reservoircontaining fragrant oil and/or insecticide oil, the device comprising awick having a first portion in communication with oil in the reservoir,and a second portion that abuts a first surface of a heat-absorbing bodythereby to transfer oil to said first surface, wherein theheat-absorbing body is disposed between the wick and the heat sourcesuch that heat from the heat source is transferred by conduction to saidfirst surface to volatilise the oil contained within the wick.

In particular, the invention provides a device for vaporising anddiffusing oils, e.g. fragrant oils or insecticide oils comprising

-   -   a container consisting of a wall having inside and outside        surfaces, the inside surface defining a cavity to receive a heat        source,    -   a reservoir suitable for containing a fragrant oil or        insecticide oil, and    -   a porous rod that communicates with the reservoir and the        outside surface of the container wall thereby to carry oil from        the reservoir to the outside surface.

The device according to the invention has numerous advantages: It isrelatively safe to use as heat is not applied to oil contained in thereservoir; heating of the oil is rapid when the device is actuated; andgiven that the heat source is always the same distance from the insidesurface of the container, the oil is exposed to an essentially constantheat source resulting in substantially uniform vaporisation of the oilover a prolonged period of time. The container may take any shape orconfiguration although preferably it is cylindrical. It should be ofsuitable dimensions such that the cavity defined by the internal surfaceof the wall can receive a heat source such as a candle or a light bulb.One end of the container has a base to provide support for the heatsource. The base may be formed integrally with the container wall, or itmay be releasably fixed to the container using mechanical fixing means,e.g. container and base may be provided with co-operating threads.

The end of the container opposing the base may be closed, e.g.terminating in a ceiling portion which, like the base, may be integralwith, or releasably fixed to, the wall of the container. Alternatively,the opposing end may be open, that is, the inner surface of thecontainer wall defines an aperture. When the container is formed withsuch an aperture, advantageously the container tapers in the directionof the aperture such that if the device were to topple over the heatsource, e.g. a candle, could not exit the device through the aperture,even in the case where the aperture is large enough to allow insertionof the candle.

The container wall may be provided with one or more apertures towardsits bottom and towards its top to permit ingress and egress of air. Thisfeature will allow air to flow through the container which is importantto ensure good burning and convection in the event that the radiant heatsource is a candle.

A variety of materials may be used in the construction of the containerprovided they are non-flammable, capable of conducting heat from theheat source from the inside surface of the wall to the outside surface,impervious and stable to fragrant and insecticide oils, and possesssufficient mechanical strength to support the container's weight and theweight of the porous rod. Suitable materials include metals such asaluminium, steel and copper, glass and ceramics, and even certainplastics materials that are heat resistant, for example certain fireresistant polyacrylates. The thickness of the container wall must besuch to impart the requisite mechanical strength and also to permitrapid heat transfer from the inside surface to the outside surface ofthe wall. For reasons of allowing light from a heat source to radiatefrom the device to enhance the aesthetics of the device, the containermay be provided with appropriately arranged apertures or certainportions or even all of the container may be formed of transparentmaterials.

The reservoir is preferably in the form of a closed receptacle. This isin contrast to the device described in U.S. Pat. No. 5,911,955 whereinthe reservoir is open in order that the heated oil contained therein mayvolatilise and escape the device by diffusion into the surroundingatmosphere. In the present invention, the oil is not volatilised in thereservoir and so the reservoir may be closed to prevent access to theoil by a user and also to prevent spillages if the device is toppledover.

The reservoir may be of any shape or configuration and may be made ofany material provided that it is impervious and stable when containingfragrant or insecticidal oils, and possesses sufficient mechanicalstrength. It, or a part thereof, may be made of transparent materialwhich has the advantage of providing the user with a visual cue when thelevel of oil is too low and needs replenishing. It may be formedintegrally with the container. However, in a preferred embodiment thereservoir is formed separately from the container and the two may beconnected prior to use by any suitable fixing means, e.g. releasablyfixed, for example by mechanical fixing means, e.g. co-operating threadsor a bayonet fitting. In a most preferred embodiment, the reservoirforms a base supporting the container.

An opening is provided in the reservoir in order to permit access of theporous rod to the oil contained in the reservoir. The opening ispreferably dimensioned such that it tightly embraces the porous rod toform a tight seal thereby preventing uncontrolled evaporation of theoil, or spillage in the event that the reservoir is toppled over.Additionally, the tight seal may promote good capillary action of theoil exiting the reservoir along the porous rod.

Depending on the nature of the porous rod, it may be difficult toachieve a desirably tight seal. Further, if the opening to receive theporous rod and the opening to permit refilling of the reservoir are thesame, it may be difficult to re-insert a porous rod made, for example ofcertain soft or pliable materials used in the manufacture of wicks.Accordingly, the reservoir in a preferred embodiment may be equippedwith a sealing member that assists insertion and removal of the porousrod from therefrom, that consists of a hollow shaft portion, defining areceiving passage to tightly receive and embrace a portion of the porousrod, and a collar portion at one end of the shaft which is adapted tofit over the opening in the reservoir in sealing relationship therewith.When the sealing member is placed over the opening in the reservoir, thecollar fits tightly over the opening to seal the reservoir and thehollow shaft containing the porous rod projects into the reservoir. Theend of the shaft remote from the collar is provided with an aperturesuch that the tip of the porous rod projects outwards of the apertureand into the oil. The sealing member may be made of any suitablematerial, e.g. plastics material or metal, and may be of the samematerial as the reservoir and is preferably formed as a one piece unitfor ease and low cost of manufacture.

The opening in the reservoir for receiving the porous rod does not haveact as an opening for refilling the reservoir, for example the reservoirmay be a use-once device disposable after use and as such a refillingoperation is not appropriate or necessary. Alternatively, the reservoirand container may be integrally formed such that the porous rod (and theopening in the reservoir therefore) may not be readily accessible to theuser. In such an embodiment there may be an additional opening in thereservoir for the refilling operations, and these additional openingsmay be provided with releasable closure means.

A reservoir which is detachable from the container as hereinabovedescribed forms an independent aspect of the present invention. It maybe provided, for example in the form of a pre-filled container that maybe made of a material that can be readily discarded after the oil isextinguished. The opening in the reservoir for receiving the porous rodmay be sealed during storage, for example by means of a screw cap or bya foil cap.

Oil transfer from the reservoir to the outer surface of the containerwall is effected by means of the porous rod. The porous rod may be ofone-piece construction which passes from the reservoir through anopening provided therein and thereafter along the outer surface of thecontainer wall.

In an alternative embodiment, however, the porous rod may be formed ofmore than one piece, e.g. two pieces. A first piece consists of aportion of elongate porous rod that projects into the oil-containingreservoir in one direction terminating in a tip, and terminates at itsother end in the form of a first porous pad, which fits over the openingin the reservoir in sealing relationship. Alternatively, when a sealingmember is employed as hereinabove described, the first porous pad,rather than itself being in sealing relationship with the opening in thereservoir, is supported on the collar portion of the sealing memberwhich provides the sealing relationship with the opening in thereservoir.

A second piece of the porous rod consists of a second porous pad whichis located on the outer surface of the container wall and conformssubstantially with the first porous pad such that when reservoir andcontainer are connected, first and second porous pads engage each otherto allow oil to flow, e.g. by capillary action, from the reservoir tothe first porous pad and there to the second porous pad. Extending fromthe second porous pad and comprising part of the second piece of theporous rod is a portion of the porous rod that is fixed to the outersurface of the container wall which receives heat from the heat source.

The portion of the porous rod which is fixed to the outer surface of thecontainer wall may, in its simplest form, consist of a single rodextending in one direction along the outer surface of the containerwall. However, in order to increase the surface area of porous rod incontact with the container wall, it may describe a convoluted pathwayacross the outside surface of the container wall, or there may be aplurality of porous rods or strips extending outwards of the secondporous pad and across the container wall. Other ways of increasing thesurface area of the rod fixed to the outer surface of the wall will beapparent to the skilled person. The porous rod may describe a decorativepath across the container wall to increase eye appeal of the device.However, irrespective of the path described by the porous rod, it isimportant that it is fixed in intimate contact with the container suchthat efficient heating of the rod and oil contained therein may beeffected.

The portion of the porous rod that extends into the reservoir may besubstantially surrounded by a barrier material which is impervious tothe oil and therefore prevents contact and therefore uptake of oil bythe porous rod. The barrier material permits exposure of the oil only toa relatively small tip portion of the porous rod. This has the advantagethat if the reservoir topples over, the tip portion lifts clear of theoil and thereby oil transfer to the container wall is discontinued toprevent possible leakage until such time as the device is restored toits correct position. It is apparent that in one embodiment of theinvention the aforementioned “barrier material” may be provided by thehollow shaft portion of the sealing member referred to hereinabove.

The porous rod may be formed of any natural or synthetic material andone skilled in the art may select materials to obtain the desired oiltransfer properties without any inventive thought and without undueburden, for example the rod may be formed of natural or synthetic, wovenor unwoven material typically used in wicks. It may take any suitableshape and is not limited to being generally circular in cross-section,for example it may have the shape of a flattened strip.

In its simplest form therefore, the device consists essentially of acontainer, a reservoir and a porous rod communicating with the reservoirand the container. Whereas this device solves the problem of spillage ofthe oil from the reservoir, in particular spillage onto the radiant heatsource, and may permit of rapid and uniform vaporisation of the oil,nevertheless the user may still come into contact with relatively smallamounts of oil if he or she brushes against an exposed portion of theporous rod. For this reason, in a preferred embodiment of the inventionthe device is provided with a shroud which substantially surrounds atleast that part of the container that carries the porous rod or strip.

The shroud serves to prevent users from touching the oil-impregnatedporous rod and also prevents the user from inadvertently touching thecontainer which may be rather hot when in use. It may be of any shape orconfiguration consistent with this purpose. However, it may take adecorative shape, for example the petals on a flower for aestheticreasons. It should not completely enclose the container in order toensure that volatilised oils may diffuse out of the device.Alternatively, the shape may be essentially practical, or evensafety-oriented. For example, the shroud may be triangular in transversecross-section and the rod from which evaporation takes place may bepositioned opposite to the side of the triangle. This ensures that, ifthe device is accidentally tipped over and the candle remains alight,the rod is never directly above candle flame, even if there is one rodper side, as is possible.

The shroud may be of separate construction with respect to the othercomponents of the device. If formed of separate construction it may befree standing with respect to the other components of the device or itmay be fixed to the container and/or the reservoir, for examplereleasably fixed to the container and/or reservoir, e.g. with mechanicalfixing means.

The heat source may be provide by a lighted candle or a light bulb orany other suitable means, for example using focused rays of the sun, andthe base of the container may be adapted accordingly to support the heatsource, for example the base may comprise candle holding means, or maycomprise a socket for receiving a light bulb.

The heat source may be introduced into the container by means obvious tothose skilled in the art. Thus, for example the heat source, e.g. candlemay be place into position in the container by means of an apertureprovided in the container for that purpose. The shroud may be removedfor this purpose or it may be provided with an aperture co-operatingwith the aperture in the container for this purpose. Other methods ofplacement and removal of the heat source, however, are not precluded aswill be obvious to the person skilled in the art.

Once actuated, the heat source heats the inner surface of the containerwall. Due to the nature of the container material and/or given that itis very thin, the heat traverses the wall and heats the oil more quicklythan in prior art devices. As the porous rod is heated so the oilcontained therein heats up, volatilises and diffuses out of the device.The evaporation of the heated oil in turn drives more oil out of thereservoir and into the rod adjacent to the heated outer surface of thecontainer wall.

When the oil or the heat source is exhausted, it is a simple matter toreplace the heat source or refill or replace the reservoir.

In a further, especially preferred embodiment of the invention, theporous rod from the reservoir to the heated surface is a wick, which hasthe form of a hollow cylinder (the “wick cylinder”) having curved innerand outer surfaces, and with a lower closed end. From this closed end, asolid rod depends in a direction away from the wick cylinder andcoaxially with it. This rod goes into liquid in the reservoir and drawsliquid into the wick cylinder. Within the wick cylinder nests inheat-conducting contact therewith a container in the sense previouslydescribed, having inside and outside walls and a cavity adapted toreceive a heat source, preferably a candle. The container, which is madefrom any suitable material that is able to transmit heat by conductionwithout being damaged by it, such as metal, glass, plastics or ceramic,acts as a heat conductor for the heat from the candle to the wickcylinder. This causes liquid to evaporate from the wick cylinder intothe atmosphere.

In a preferred embodiment, the wick cylinder is encased in a cap,preferably an extension of a closure of the reservoir. This cap has anannular transverse cross-section and encases the wick cylinder on bothsides, except for orifices as hereinafter described. The cap has acentral re-entrant portion that matches the shape of the wick cylinder,and that is dimensioned such that the container nests within the cap andis in heat-conducting contact therewith. This cap has at least oneorifice on the outer side thereof, remote from the candle, through whichvolatilised liquid can escape from the wick cylinder. In a variant ofthis, the cap is equipped with an upper cap, which is rotatable aboutthe cap. This upper cap bears a number of orifices equal to that of thecap, the two sets of orifices being sized and placed so that rotation ofthe upper cap can partially or completely block the orifices of the capand hinder or prevent vaporised liquid from escaping.

In a preferred version of this embodiment, a flange extendscircumferentially from the container from a point above the end of thewick cylinder, to such an extent that the wick is protected frommaterial falling from above. Practically, this means that it extendsbeyond the diameter of the wick cylinder, or, when a cap or an upper capis used, beyond the diameter of the cap or upper cap. This flange isgenerally planar and circular, but may be made in any desired shape ordimension. It gives an added safety factor in that, if the candle is litby means, say, of a match and the match is dropped, there is nopossibility of the match contacting the wick cylinder and igniting anyflammable material therein. The flange may extend from the uppercircumferential lip of the container, or, in the case of the containerextending substantially beyond the rod cylinder, from some pointintermediate between the top of the wick cylinder and the upper lip ofthe container, in the form of a vane. The flange is preferablyperforated, to permit vaporising liquid from the wick cylinder that isemerging from an orifice or orifices below the flange, to pass through.

In this embodiment, the porous rod or wick may be formed in two parts,the rod that makes contact with the liquid and the cylinder with theclosed lower end provided with an aperture to receive the rod.Alternatively, the cylinder may be made in a cup shape and the rodextending downwards into the liquid may be equipped with a porous flatplate, on which plate the cup sits, and liquid passes from the flatplate into the porous cup. A further possibility is that the wick may bemade in a single piece.

The device according to the present invention is useful to diffuse oils,e.g. fragrant oils or insecticide oils, into surroundings in needthereof. Any of the oils known in the art that find use in vaporisingand diffusing devices may be used in the device of the presentinvention. In addition to the use of neat oils, the device may also beemployed to vaporise and diffuse oils in suitable solvents, for exampleoils in water or in ethanol.

The invention is now further described with reference to the drawings.These drawings depict preferred embodiments and do not limit theinvention in any way.

FIG. 1 depicts a view of the device in cross section with candle-holderinserted.

FIG. 2 depicts the device in cross section with the candle holderremoved

FIG. 3 depicts the reservoir in cross section disconnected from theremainder of the device.

FIG. 4 depicts a longitudinal cross-section of a further preferredembodiment of the invention.

FIG. 5 depicts a longitudinal cross-section of a variation of theembodiment of FIG. 4.

The device shown in FIG. 1 is in the form of a lantern and consists of areservoir (1), in the form of a broad base to impart stability to thedevice, containing oil (3). The reservoir is sealed to prevent spillage,with a sealing member (5). The sealing member is essentially T-shaped incross section and consists of a hollow shaft (16) containing a portionof a porous rod or strip (6) which extends downwardly into the oil (3),and an integrally formed collar portion (17). Seated on top of thecollar portion (17) is a porous pad (4) which is in contact, and may beintegral, with the porous rod or strip (6). The reservoir (1) has a neckportion (18) equipped with a thread (19) on its outer surface.

Referring to FIG. 2, the container consists of a generally cylindricalopen-topped funnel (7). Towards its bottom, the funnel (7) is providedwith an aperture (12) adapted to receive the heat source, e.g. a candle(14). The candle is situated in a candle holder (13) and the candleholder may be slid laterally in and out of the aperture (12) when thecandle needs to be removed and replaced. On the outer surface of thefunnel (7) there is fixed a porous rod (8) which contains oil drawn fromthe reservoir, for example by capillary action. The bottom of the funnelis provided with a base (20) which supports the candle holder (13) whenit is inserted in the device. The base is provided with a small aperture(21) through which the porous rod (8) extends to a position below thebase where it contacts, and may be integral with, a porous pad (15) (inthe embodiment shown 8,15 are integral). The container is equipped witha thread (22) below the base (20) which is adapted to co-operate withthe thread (19) on the neck portion of the reservoir (1) to releasablyconnect container and reservoir.

Surrounding the funnel (7) is a shroud (9) which is formed integrallywith the funnel (7). The shroud has an aperture (23) to permit egress ofvolatilised oil. The shroud is also provided with an aperture (24) whichis in general alignment with the aperture (12) in the funnel (7) topermit insertion and removal of the candle holder (13).

In use, the reservoir (1) is fixed to the funnel (7) by the co-operatingthreads (19,22) such that the porous pads (4) and (15) come intocontact. Oil then rises through capillary action via (6), (4) and (15)to the porous rod (8). The lighted candle (14) and its holder (13) areinserted into the funnel via the apertures (12, 24). Radiant heat fromthe candle heats the wall of the funnel (7) which, in turn, heats andvolatilises the oil in the rod (8). The oil vapours then pass up thespace between the container and the shroud and out of the aperture (23).The act of vaporisation of oil from the porous rod (8) acts to drawfurther oil from the reservoir via (6, 4, 15) to the porous rod whereit, in turn, is vaporised.

When the oil in the reservoir is exhausted, the reservoir and funnel aredisconnected; the sealing member (5) is removed and either fresh oil ispoured into the reservoir or the reservoir is discarded and a newreservoir filled with oil is provided. The device may be reconnectedcarrying out these operations in reverse. Similarly, once the candle isexhausted it is removed with its holder through the apertures in thefunnel and shroud; a fresh candle is inserted into the holder and is litbefore the holder and freshly lit candle are placed into the funnel.

When disconnected from the device (see FIG. 3) the reservoir may beclosed with a cap (2) that may be equipped with a thread adapted toco-operate with the thread (19) on the outer surface of the neck portion(18). Closure of the reservoir need not however, be achieved using athreaded cap, for example closure may be achieved using a removable foilsheet.

Referring now to FIG. 4, a reservoir 4 containing a volatile liquid 5 isequipped with a porous wick 7, having the shape of a hollow cylinderclosed at the bottom end, with a cylindrical solid rod projectingcoaxially with and downwardly from the closed bottom end. This wick isheld in position by a wick support 6, which has the form of a funnel,the downwardly-projecting “nozzle” of the funnel being dimensioned so asto accommodate the solid cylindrical rod portion of the wick 7 andtherefore support the wick.

The reservoir 4 has a neck 8 to which a cap is attached by cooperatingscrew threads. The cap has two parts, an upper cap 9 and a lower cap 10.The lower cap bears at its lower end the abovementioned screw threads.The upper part of this cap has a cylindrical-shaped re-entrant portion11 with a flat bottom, adapted to receive a candle container 13, whichholds a candle 12. The walls of the cap surrounding the re-entrantportion are hollow (in transverse cross-section they have the form of anannulus) and are adapted to accommodate the circular wall of thecylindrical wick 7. The face of the cap wall remote from the candle 12has apertures 14 adapted to release evaporating liquid from thecylindrical portion of the wick 7 within the cap.

The upper cap is fitted to the lower cap by snap fitting by means ofcooperating circumferential projections 15 on the outer wall of thelower cap and the inner wall of the upper cap. The upper cap isbasically a cylinder with a turned-over top 16, which top rests on topof the hollow wall of the lower cap. The relative dimensions of theupper and lower caps are such that the upper cap can be rotated aroundthe lower cap. The upper cap is also provided with a series of apertures17 placed circumferentially around it, and arranged with respect to theapertures 14 of the lower cap so that the access to the atmosphere ofthe vapour from the wick can be partially or completely closed off byturning the upper cap.

The candle container 13 has the form of a hollow metal cylinder, open atthe upper end, the lower closed end supporting a candle 12. At the upperopen end of the container, there is a planar, circumferential,perforated flange 18 formed as a continuation of the upper end of thecontainer, this flange resting on the turned-over top 16 of the uppercap 9.

In operation, the candle 12 is lit and the resulting heat is conductedthrough the container 13 and the hollow walls of the lower cap 9 to thecylindrical part of the wick 7, thus causing evaporation of liquid fromthe wick to the atmosphere via the apertures 14 and 17.

The flame of the candle is completely isolated from the liquid and theflange protects the wick from any contact with any ignited materialinadvertently falling from above.

FIG. 5 depicts a modification of the apparatus of FIG. 4. In this case,the container 13 is equipped with a cylindrical extension 19 extendingupwardly from the candle. In this case, the flange remains in the sameplace with respect to the lower cap 9, but the cylindrical part of thecontainer now extends above it. This increases the surface areaavailable for heating and allows better evaporation.

1. A device for vaporising and diffusing oils comprising: a containermade of heat-conducting material and consisting of a wall having insideand outside surfaces, the inside surface defining a cavity to receive aradiant heat source, a reservoir suitable for containing a fragrant oilor insecticide oil, and a porous rod that communicates with thereservoir and the outside surface of the container wall thereby to carryoil from the reservoir to the outside surface, the porous rod being awick that has a portion that has the form of a cylinder having inner andouter curved sides and being closed at one end, from which closed enddepends coaxially with and away from the cylinder, a solid cylindricalrod adapted to contact the oil; and at least part of the container hasthe form of a cylinder that is adapted to hold a heat source and that isconfigured so as to be nestable within the wick cylinder and inheat-conducting contact therewith.
 2. A device according to claim 1,wherein tile curved surface of the wick cylinder is completelysurrounded on both inner and outer sides by a cap having a re-entrantportion into which fits the container in heat-conducting contact, thecap having at least one orifice on a surface remote from the container,to permit the vaporisation of liquid into the atmosphere.
 3. A deviceaccording to claim 1, wherein the container comprises a flange extendingoutwardly circumferentially therefrom, to such an extent that the rod isprotected from contact with material falling vertically from above.
 4. Adevice according to claim 1 wherein the container is surrounded by ashroud which prevents the porous rod being contacted by a user.
 5. Adevice according to claim 1 wherein the heat source is a candle or alight bulb.
 6. A device according to claim 5 wherein the reservoir andthe container are detachable.
 7. A device according to claim 5, whereinthe heat source is a candle and the container is constructed such thatthe candle is at least partially visible through it.
 8. A deviceaccording to claim 1 in the form of a lantern comprising a container, areservoir serving as a base for the container, and a shroud surroundingthe container.
 9. A device according to claim 1 wherein the said oilsare fragrant oils or insecticide oils.